Soap compositions



United States Patent Olhce 3,536,628 Patented Oct. 27, 1970 3,536,628 SOAP COMPOSITIONS Frank Lancashire, Procter & Gamble, Ltd., Hedley House Gosforth, Newcastle-upon-Tyne, England No Drawing. Filed Dec. 22, 1965, Ser. No. 515,738 Int. Cl. Clld 9/34, 9/32, 9/30 U.S. Cl. 252-117 Claims ABSTRACT OF THE DISCLOSURE where X can be hydrogen, OH, or a carbonyl oxygen; and Y can be H, OH, CH3, CH2PO3H2, CH CH(PO H except when X is a carbonyl oxygen, Y has no value. The weight ratio of the synthetic detergent to phosphonic acid salt should be from about 1:4 to about 4: 1, and preferably from about 1:2 to about 2:1.

This invention relates to soap compositions particularly suitable for use in hard Water.

Soap is an excellent detergent, but it has a serious disadvantage. This disadvantage is its tendency to react with the metallic ions which are responsible for the hardness of water, notably calcium and magnesium ions. This reaction forms an insoluble curd, also known as lime soap. This insoluble lime soap forms undesirable deposits on the inside surfaces of washing machines. It is also deposited on fabrics which are washed in hard water with soap as the detergent. These deposits give rise to a poor hand, disagreeable odor and poor color of the washed fabrics. It also reduces the water-absorbency of fabrics, e.g., towels, which have been washed with soap in hard water.

Attempts have been made to minimize this disadvantage of soap by the use of sequestering agents which prevent the formation of lime soap by forming complexes with the metallic ions concerned. Other attempts involved replacing all or part of the soap in the washing composition by synthetic detergents, which do not form insoluble compounds with the metallic ions of hard water. Moreover, the synthetic detergents also serve to disperse the insoluble lime soap and so inhibit its deposition on the washing machine surfaces and on the washed fabrics. However, the proportion of synthetic detergents or sequestering agents required for this purpose is high and the products are costly.

It is an object of this invention to provide a novel soap-based detergent composition. It is a further object of this invention to provide a soap-based detergent composition which is free of the disadvantages described above.

It has now been unexpectedly discovered that the lime soap dispersing power of certain organic surface active agents can be enhanced to a surprising degree by the addition of certain alkali metal soluble phosphonic acid derivatives in certain essential proportions. The effect of these two components has been found to be highly synergistic in curd dispersing power. This unexpected discovery now allows the economical formulation of a high soap content detergent composition that has a greatly reduced tendency to form lime soap.

According to the present invention, a soap composition having improved curd-dispersing properties consists es sentially of from about 40% to about 95% of a higher fatty acid soap; from about 5% to about 60% of a mixture of at least one synthetic detergent selected from the group consisting of (1) a detergent which contains in its molecular structure a zwitterion or a semi-polar bond and (2) an amphoteric synthetic detergent; and at least one watersoluble salt of a phosphonic acid of the general formula:

where X can be H, OH or carbonyl oxygen; and Y can be H, OH, CH3, CH2PO3H2,

except when X is a carbonyl oxygen, Y has no value. The weight ratio of the synthetic detergent to phosphonic acid salt should be from about 1:4 to about 4:1, and preferably from about 1:2 to about 2: 1.

Preferably, the fatty acid soap should comprise from about to about 90% by weight of the detergent composition, and the synergistic curd dispersing mixture of the synthetic detergent and the phosphonic acid salt should comprise from about 10% to about by weight of the composition.

The higher fatty acid soaps suitable for use as the present invention are the sodium, potassium, and the alkylolammonium salts of higher fatty acid (C -C Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium tallow and coconut soap, Similarly, palm and palm kernel oil are useful starting materials, as are synthetic fats simulating, for instance, tallow.

As mentioned above, the synthetic detergents useful in the present invention can be of three types, those which contain in their molecular structure a zwitterion or a serni-polar bond or an amphoteric synthetic detergent.

The zwitterionic detergents are aliphatic quarternary ammonium compounds in which one aliphatic substituent contains from about 10 to about 18 carbon atoms and another aliphatic substituent contains a water solubilizing anionic group. Examples of such compounds are water salts of alkylated betaines and sultaines of the general formula:

where R is an alkyl group of from about 10 to about 18 carbon atoms, R and R are alkyl groups of from 1 to about 3 carbon atoms, R, is an alkylene or hydroxy alkylene group of from 1.to about 4 carbon atoms, and X is a carboxylic acid or sulphonic acid anion. Especially preferred compounds are 3-(N,N-dimethyl-N-alkyl)ammonio 2 hydroxy propane l sulphonates and 3- (N,N-dimethyl N alkyl)ammonio-propane-l-sulfonates in which the alkyl group contains from about 10 to about 18 carbon atoms and preferably 12 to 16.

Useful synthetic detergents which contain semi-polar bonds are tertiary amine oxides of the general formula R R R N O and tertiary phosphine oxides of the general formula R R R P- O where R is an alkyl, alkenyl, or hydroxy alkyl radical of from about 10 to about 18 carbon atoms and R and R are each alkyl or monohydroxy alkyl radicals of from 1 to about 3 carbon atoms; for example, dimethyl dodecyl amine oxide, diethanol dodecyl amine oxide, dimethyl decyl amine oxide, dimethyl tetradecyl amine oxide, or dodecyl bis (hydroxymethyl)phosphine oxide, tetradecyl dimethyl phosphine oxide, dimethyl dodecyl phosphine oxide; and sulfoxides of the general formula R R S O in which R; is an alkyl, alkenyl, hydroxy alkyl or alkoxy alkyl radical of from about to about 18 carbon atoms and R is methyl or ethyl. Examples are 3-hydr0xytridecylmethyl sulfoxide, or the preferred compound, 3-hydroxy4-decoxy-butylmethyl sulfoxide.

The amphoteric synthetic detergents which are suitable for use in the compositions of the invention are synthetic detergents which contain both an acidic and a basic function in their structure. The acidic group can be a carboxylic, sulfuric, sulfonic or phosphoric acid group and the basic group contains a non-quaternary nitrogen atom. The following are examples of suitable amphoteric synthetic detergents;

(a) water-soluble salts of alkylamino alkane carboxylic acids of the general formula where X is 1 or 2; a specific example is a dodecylamino methane carboxylic acid sodium salt (b) water-soluble salts of N,N-dialkyl ethylene diamine diacetic acids of the general formula /N-CH2-CH2-N HOOC-CHz CHzCOOH a specific example is a N,N'-dodecyl ethylene diamine diacetic acid sodium salt (6) water-soluble salts of N-alkyl taurines of the general formula R-NH-CH -CH -SO H a specific example is a N-methyl taurine sodium salt. (d) water-soluble salts of N-alkyl-N'-sulfophenylethylene diamines of the general formula a specific example is a N-methyl-N'-sulfophenyl ethylene diamine sodium salt.

In all of the above general formulas R represents an alkyl radical of from about 10 to about 18 carbon atoms.

The preferred amphoteric synthetic detergent is the sodium salt of N-la'uryl-beta-alanine.

The specific synthetic detergents mentioned above are merely illustrative and representative of the suitable classes of detergents. It is to be understood the mixtures of these detergents can also be used to advantage according to the teaching of the present invention.

The phosphonic acid salts which are suitable for use in the compositions of the invention are the alkali metal salts of ethane-l-hydroxy-1,1-diphosphonic acid; ethane-Z-carboxy-1,1-diphosphonic acid; hydroxymethanediphosphonic acid; ethane-2,1,1-triphosphonic acid; carbonyldiphosphonic acid; and propane-1,1,3,3-tetraphosphonic acid; propane-1,1,2,3-tetraphosphonic acid; and propane-1,2,2-3-tetraphosphonic acid.

The preferred phosphonic acid salt is the trisodium salt of ethane-l-hydroxy-l,l-diphosponic acid.

Some of the aforementioned zwitterionic, semi-polar, or amphoteric surface active agents have some limited lime soap dispersing power. According to this discovery, this power is synergistically increased to a surprising degree by the admixture in certain amounts of the specified phosphonate salts, which themselves have limited lime soap dispersing power. This synergistic increase in the lime soap dispersing power is illustrated by the following tests:

TEST I A series of solutions were prepared by dissolving 2 grams of a mixture of 3-hydroxy-4-decoxybutylmethyl sulfoxide (HDBMS) and the trisodium salt of ethane-lhydroxy-l,1-diphosphonic acid (EHDP) in 400 ml. of 15 gr./U.S. gal. hard water at 130 F. The pH of each solution was adjusted to 10.0. The various mixtures used contained 100% EHDP; 80% EHDP/20% HDBMS; 60% EHDP/40% HDBMS; 40% EHDP/60% HDBMS; 20% EHDP/80% HDBMS, and 100% HDBMS, repectively.

A 1% solution of sodium soap obtained from 20% coconut oil and 80% tallow was run into the solution from a burette with constant agitation of the solution until a cloudy solution was obtained. The number of milliliters of soap solution required to produce a cloud is a measure of the lime soap dispersion power of the mixture under test. The results obtained are tabulated below:

TABLE I N o. of mls. of 1% soap solu- HDBMS, tion to produce EHDPY percent percent a cloud In the preceding example, the 3-hydroxy-4-decoxybutylmethyl sulfoxide compound can be replaced by dodecydimethyl amine oxide or dodecyldimethyl phosphine oxide, and equally excellent curd disperising properties are obtained. The EHDP can be replaced in whole or in part by the sodium or potassium salts of ethane-2- carboxy-1,1-diphosphonic acid, hydroxymethanediphosphonic acid, ethane-2,1,l-triphosphonic acid, carbonyldiphosphonic acid or propane-1,1,3,3-tetraphosphonic acid.

TEST II A series of solutions were prepared by dissolving 2 grams of a mixture of the sodium salt of N-lauryl betaalanine (LBA) and the trisodium salt of ethane-l-hydroXy-1,1diphosphonic acid (EHDP) in 400 ml. of 15 gr./U.S. gal. hard water at 130 F. The various mixtures used were 100% EHDP; EHDP/20% LBA; 60% EHDP/40% LBA; 40% EHDP/60% LBA; 20% EHDP/80% LBA; and 100% LBA. The pH of each solution was adjusted to 10.0. Into each solution a 1% solution of sodium soap, obtained from a mixture of 20% coconut oil and 80% tallow, was run from a burette with constant agitation of the solution until the solution became cloudy. The number of milliliters of 1% solution required to produce a cloud is a measure of the lime soap dispersion power of the mixture. The results are tabulated bellow.

TABLE II N o. of mls. of 1% soap solutlon to produce EHDP, percent; LBA, percent a cloud The results in both tables show the totally unexpected synergistic high lime soap dispersing power of mixtures of EHDP/HDBMS and EHDP/LBA of weight ratio 1:4

to 4:1, especially about 1:2 to 2:1 of EHDP to surfactant, compared with that which would be expected from the individual lime soap dispersion power of the components of the mixtures.

While the compositions of the invention may be produced in any conventional form such as bars, tablets, powders, liquids or pastes, the invention is particularly suitable for granular washing compositions such as are used for domestic laundering. Such compositions preferably contain at least 40% by weight of soap, and may additionally contain other usual ingredients of household washing compositions. Examples of such ingredients are alkaline builder salts, e.g., sodium carbonate and sodium silicate; peroxy bleaching agents, e.g., sodium perborate; optical whitening agents; color and perfume.

A further advantage of the compositions of the invention is that solutions of the compositions do not suds appreciably until all the hardness of the water has been destroyed and the solution contains sufficient free soap to have effective washing power. This delayed sudsing avoids under-usage of the composition. When high sudsing synthetic detergents are used in conjunction with soap in hard water, sudsing of the solution is often produced before the concentration of free soap in the solution has become high enough to give effective detergency. This premature sudsing may cause the user of the composition to add insufficient amounts of composition to the washing solution. Poor cleaning will be the result of this insufficient addition. This problem can be avoided by means of the use of the compositions of the invention, since they do not suds significantly until sufficient soap for effective washing is present.

The compositions of the invention give effective lime soap dispersion during the washing stage. If the Washed goods are rinsed in hard water, the washing solution remaining in the fabric is diluted by a large proportion of the added hard water. Under these conditions, some lime soap in undispersed form may be formed. According to a further feature of the invention, the tendency for this to happen can be reduced or entirely eliminated by including in the soap composition a low-sudsing nonionic detergent. Moreover, low-sudsing nonionic detergent. Moreover, low-sudsing nonionic detergents are used to avoid the appearance of suds in the rinse water.

Suitable alkylene oxide-containing nonionic synthetic detergents of the type which are useful in this embodiment of the present invention are:

(1) The polyethylene oxide condensates of alkyl phenols and dialkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to about to 30 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octene, or nonene, for example.

(2) Alkylene oxide-containing nonionic detergents derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. Here again a series of compounds are contemplated whose characteristics can be controlled by achieving a desired balance between the hydrophobic and hydrophilic elements. For example, compounds containing from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5,000 to about 11,000 resulting from the reaction of ethylene oxide groups with a hydrophobic base constituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2,500 to 3,000, are satisfactory.

(3) The condensation product of aliphatic alcohols having from 8 to 22 carbon atoms, in either straight chain or branched chain configuration, with ethylene oxide, e.g., a coconut alcohol-ethylene oxide condensate having from about 4 to 30, preferably from 5 to 15,

moles of ethylene oxide per mole of coconut alcohol. The coconut alcohol fraction which is preferred is a distilled coconut alcohol having from 10 to 1-6 carbon atoms, with the approximate chain length distribution being from 2% C 66% C12, 23% C and 9% C Another preferred compound is the condensation product of tallow derived alcohol and from about 3 to about 15 moles of ethylene oxide per mole of tallow alcohol; a specific illustration being the condensation reaction product of one mole of tallow alcohol and 4 moles of ethylene oxide (TE (4) A well known class of alkylene oxide-containing nonionic synthetic detergents of this type is made available on the market under-the trade name of Pluronic. These compounds are formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of the molecule which, of course, exhibits water insolubility, has a molecular weight of from about 1500 to 1800. The addition of polyoxyethylene radicals to this hydrophobic portion tends to increase the water solubility of the molecule as a whole and the liquid character of the product is retained up to the point where polyoxyethylene content is about 50% of the total weight of the condensation product.

(5) Specific illustrations of the foregoing classes include the following which are merely illustrative of the type intended: nonyl phenol condensed with either about 5 or about 30 moles of ethylene oxide per mole of phenol and the condensation products of coconut alcohol with an average of either about 4 or about 15 moles of ethylene oxide per mole of alcohol and the condensation product of about 15 moles of ethylene oxide with one mole of tridecanol. Other illustrative examples are dodecylphenol condensed with 12 moles of ethylene oxide per mole of phenol; dinonylphenol condensed with 15 moles of ethylene oxide per mole of phenol; dodecyl mercaptan condensed with 10 moles of ethylene oxide per mole of mercaptan; bis-(N-Z-hydroxyethyl) lauramide; nonyl phenol condensed with 20 holes of ethylene oxide per mole of nonyl phenol; myristyl alcohol condensed with 10 moles of ethylene oxide per mole of rnyristyl alcohol; lauramide condensed with 15 moles of ethylene oxide per mole of lauramide; and diisooctylphenol condensed with 15 moles of ethylene oxide.

The preferred nonionic detergent is the condensation product of one mole of hydrogenated tallow fatty alcohol with 4 moles of ethylene oxide. The proportion of low sudsing nonionic detergent in the composition may be up to about 20% by weight of the soap content, and preferably from at least about 2% to about 15%, by weight of the soap content of the composition.

The invention is illustrated by the following examples:

EXAMPLE I A spray dried granular composition is prepared to give the following finished product composition:

Percent by wt.

Sodium soap (20% coconut oil, tallow) 52 N-lauryl-beta-alanine sodium salt 6 Ethane-1-hydroxy-1,l-diphosphonic acid trisodium salt 4 Sodium silicate solids (ratio SiO :Na O=2.4:l) 10.25

Condensation product of 1 mol hydrogenated tallow fatty alcohol with 4 moles ethylene oxide 2 7 EXAMPLE II A spray dried granular soap composition is produced to give the following finished product composition:

Percent by wt Sodium soap (20% coconut oi1:80% tallow) 3 (N,N-dimethyl-N-dodecyl)ammonio-Z-hydroxypropane-l-sodium sulfonate 6 Ethane-l-hydroxy-l,l-diphosphonic acid trisodium salt 4 Sodium silicate solids (ratio SiO :Na O:2.4:1) 10.25 Condensation product of one mole of hydrogenated tallow fatty alcohols with 4 moles of ethylene oxide 2 The product is prepared by spray-drying an aqueous slurry of all of the ingredients of each example except the sodium perborate and perfume; perfume is sprayed onto the spray-dried granules which are then mixed with sodium perborate.

In use in a household washing machine using water of about gr./U.S. gal. hardness, the product of each example gives no suds below the concentration at which all the hardness has been removed and the soap concentration is etfective for washing. The washing solution is free from lime soap scum and no deposit of lime soap is left in the washing machine. During rinsing, the rinse water is free from lime soap scum and also free from suds.

Similar results are obtained if the N-lauryl-beta-al-anine salt is replaced by the sodium salt of N-alkyl glycine in which the alkyl radical is derived from coconut oil and if the ethane-l-hydroxy-l,l-diphosphonic acid trisodium salt is replaced by sodium salts of the other phosphonic acids named above.

Additional illustrative examples are:

EXAMPLE III A soap composition is prepared to give the following product composition:

Percent by wt.

Sodium soap coconut oil, 80% tallow) 70 3 (N,N-dimethylN-hexadecyl)ammonio-2-hydroxypropane-l-sulfonate Ethane-1-hydroxy-1,1 diphosphonic acid trisodium salt 1O Moisture 14 Miscellaneous 1 EXAMPLE IV A soap composition is prepared to give the following production composition:

Percent by wt.

Sodium soap (40% coconut oil, 60% tallow) 3-(N,N-dimethyl-N-dodecyl) ammonio-propane-1-sulfonate Ethane 2 carboxy-Ll-diphosphomc acld trisodium salt Moisture 14 Miscellaneous 1 EXAMPLE V A soap composition is prepared to give the following product composition:

Miscellaneous 8 EXAMPLE VI A spray-dried granular composition is prepared to give the following finished product composition:

Percent by wt.

Sodium soap (100% coconut) 50 Dimethyl hexadecyl phosphine oxide 10 Ethane-2,1,1-triphosphonic acid pentasodium salt 30 Water 9 Miscellaneous 1 EXAMPLE VII A spray-dried granular composition is prepared to give the following finished product composition:

Percent by wt.

Sodium soap coconut oil, 20% tallow) 70 3-hydroxy-4 decoxy-butylmethyl sulfoxide 5 Carbonyldiphosphonic acid trisodium salt 10 Water 10' Miscellaneous 5 EXAMPLE VIII A spray-dried granular composition is prepared to give the following finished product composition:

Percent by wt.

A spray-dried granular composition is prepared to give the following finished product composition:

Percent by wt.

Sodium soap tallow) 60 Dimethyl tetradecyl amine oxide 5 Propane 1,1,2,3 tetraphosphonic acid pentasodium salt 10 Condensation product of 1 mole of hydrogenated tallow fatty alcohol with 4 moles of ethylene oxide 10 Water -l 10 Miscellaneous 5 EXAMPLE X A spray-dried granular composition is prepared to give the following finished product composition:

Percent by wt. Sodium soap (50% coconut oil, 50% tallow) 55 Dimethyl hexadecyl phosphine oxide 7 Propane 1,2,2,3 tetraphosphonic acid pentasodium salt 20 Nonyl phenol condensed with either about 5 or about 30 moles of ethylene oxide per mole of alcohol 3 Water 10 Miscellaneous 5 Germicidal agents can be added to the soap compositions of the present invention to render the products antiseptic in quality.

The invention described hereinabove represents a substantial improvement over prior art practices according to which attempts were made to solve the problem of curd dispersion by the adidtion of sequestering agents to soap. One especially troublesome problem was that which arose from the use of soap detergent compositions in washing machines and boilers which contained internal heating coils to warm the water. The lime soap and curd tends to form deposits on these heating elements and eventually seal them 01f. One prior art solution to this problem called for admixing soap with about 5% by weight of the soap of an alkali metal salt of certain diphosphonic acids such as ethane-1-hydroxy-1,1-diphosphonic acid and ethane- 1,1,2-triphosphonic acid. In another prior art method, sodium nitrilotriacetate was suggested for the same purpose as the just mentioned polyphosphonic acids.

As seen from Tables I and II above, the specifically pro portioned combinations of the synthetic detergents and the phosphonic acid salts described herein oifer superior valuable synergistic curd dispersing properties and are better adapted for protection for the internal washing machine heaters mentioned above.

The foregoing description of the invention has been presented describing certain operable and preferred embodiments. It is not intended that the invention should be so limited since variations and modifications thereof will be obvious to those skilled in the art, all of which are within the spirit and scope of this invention.

All of the percentages given above are by weight unless otherwise specified.

What is claimed is:

1. A soap composition having improved curd-dispersing properties consisting essentially of (I) from about 40% to about 95% of a higher fatty acid soap;

(II) from about to about 60% of a synergistic curd-dispersing mixture of (A) at least one synthetic detergent selected from the group consisting of (1) 3-hydroxy-4-decoxybutylmethyl sulfoxide;

and (2) N-lauryl beta-alanine; and (B) at least one alkali metal salt of ethane-1- hydroxy-1,1-diphosphonic acid; the ratio by weight of said synthetic detergent to said phosphonic acid salt being from about 1:4 to about 4: 1.

2. A soap composition according to claim 1 containing from about 45% to about 90% by weight of said higher fatty acid soap; from about to about 55% by weight of said synergistic mixture of synthetic detergent and phosphonic acid salt, and in which the ratio, by weight, of said synthetic detergent to said phosphonic acid salt is from about 1:2 to about 2: l.

3. A soap composition according to claim 1 wherein the fatty acid soap is a 220% mixture of tallow and coconut soap, and the phosphonic acid salt is trisodium ethane-l-hydroxy-1,1-diphosphonate.

4. The composition of claim 1 which also contains up to about 20% by weight of the soap content of an alkylene oxide containing nonionic synthetic detergent.

5. The composition of claim 4 which contains from about 2% to about 15% of said nonionic synthetic detergent.

References Cited UNITED STATES PATENTS 3,159,581 12/1964 Diehl 252152 3,214,454 10/1965 Blaser et al. 260429.9 3,318,817 5/1967 Smith 252137 3,297,578 1/ 1967 Crutchfield et a1 25299 3,290,254 12/1966 Anderson 252138 3,368,978 2/1968 Irani 252137 3,392,121 7/1968 Gedge 252137 XR 3,400,148 9/1968 Quimby 25289 XR 3,422,021 1/ 1969 Roy '252-89 XR 3,382,180 5/1968 Priestley et al. 252152 FOREIGN PATENTS 775,364 5/ 1957 Great Britain. 943,628 12/ 1963 Great Britain.

OTHER REFERENCES Surface Active Agents, vol. I, by Schwartz & Perry, 1949, pp. 372-373.

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US. Cl. X.R. 252121, 132, 161

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,536,628 Dated October 27, '1970 I ve Frank Lancashire It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, llne 38, (C C should be (C C Column 5, lines 42 to 43, Moreover, low-sudsing nonionic detergent." should be deleted.

Column 6, line 73, "association" should be associated JJEGNED NW SE15!) gSEAL) 2. Hum, mu flomissione-r of Patents Edward ll. Fletcher, 11'. 

